1. Field of the Invention
The present invention relates to an array-type light-receiving device.
2. Description of the Related Art
Japanese Patent No. 4771185 discloses a technique that relates to a light-receiving device having photosensitivity in the near-infrared region. The light-receiving device includes a stacked semiconductor layer on a semiconductor substrate. The stacked semiconductor layer includes an optical absorption layer and a diffusion concentration distribution control layer. The optical absorption layer includes a p-n junction. In addition, the optical absorption layer includes a multi quantum well (MQW) structure. The diffusion concentration distribution control layer is in contact with a surface of the optical absorption layer opposite the semiconductor substrate. The diffusion concentration distribution control layer has a smaller bandgap energy than that of the semiconductor substrate. The p-n junction is formed in the optical absorption layer by selective diffusion of a p-type impurity such as zinc (Zn) impurity. The impurity concentration in the diffusion concentration distribution control layer is reduced toward the optical absorption layer. The impurity concentration in the diffusion concentration distribution control layer is 5×1016/cm3 or less. The semiconductor substrate is an InP substrate.
An array-type optical detector on a S-doped InP substrate is disclosed in Joseph Boisvert, Takahiro Isshiki, Rengarajan Sudharsanan, Ping Yuan, Paul McDonald, “Performance of Very Low Dark Current SWIR PIN Arrays”, Proceeding of SPIE Vol. 6940, 69400L-1 (2008). In order to form the array-type optical detector, a stacked semiconductor layer is formed on a 2-inch S-doped InP substrate by a metal-organic vapor phase epitaxy (MOVPE) method. The InP substrate has a (100) plane orientation. An array detector on a GaSb substrate is disclosed in Robert Rehm, Martin Walthera, Johannes Schmitza, Frank Rutza, Andreas Worla, Ralf Scheibnerb, Johann Zieglerb, “Type-II Superlattices—The Fraunhofer Perspective”, Proceeding of SPIE Vol. 7660, 76601G-1 (2010). A stacked semiconductor layer for forming the array detector is formed on a 3-inch GaSb substrate by a molecular beam epitaxial growth (MBE) method.